The goal of this research is to study the electrical response properties and morphological features of the cat inferior colliculus (IC) neurons that are sensitive to binaural stimulation, using extra- and intracellular recording techniques as well as light and electron microscope analysis. A primary issue is to determine if high frequency nuerons are sensitive to differences in the time of arrival of the sound at each ear. Although interaural time was thought not to be a cue for localizing high frequency signals, recent psychoacoustical studies have demonstrated that human listeners can reliably lateralize these signals if the high frequency source is pulsed or modulated within a low frequency envelope. Consistent with these psychoacoustic results, recent physiological findings indicate that high frequency IC neurons are indeed sensitive to changes in interaural time delay when pulsed, or modulated, high frequency stimuli are used. More over, the interaural time sensitivity of these neurons at first approximation is similar to that seen in low frequency neurons. Thus, a unified schema of neural mechanisms underlying binaural information processing may be obtained through the study of binaural interaction of high frequency neurons in conjunction with systematic comparisons to previous work on low freuency neurons. Moreover, the proposed intracellular recording, dye injection and subsequent morphological analysis may provide insights into the synaptic mechanisms responsible for binaural signal processing at the level of the IC. In the natural situation, most stimuli are received binaurally. Thus the elucidation to neural mechanisms underlying binaural interaction is fundamental to understanding auditory information processing.